The crash yesterday of a hot-air sightseeing balloon appears to be the second-deadliest balloon accident on record. It killed everyone aboard, 16 people.

The balloon crash in Texas produced the highest death toll of any such accident “in the Western Hemisphere”, according to Balloon Federation of North America spokesman, Jeff Chatterton.

“There are thousands of balloons that go up every year,” he said. “This is unspeakably tragic but it is rather unique.”

Ballooning is usually a safe sightseeing activity and is highly popular. More than 150 commercial hot air balloon companies operate in North America, Chatterton said.

The balloon basket caught fire. The craft also became entangled in high-voltage power lines, though the order in which those events occurred has yet to be established.

The US Federal Aviation Administration (FAA) said the crash occurred about 50 kilometres south of Austin.

Local media said the balloon belonged to the Heart of Texas Balloon Company, ABC News reported. It bore a yellow smiley face and sunglasses motif, set against a red, white and blue background, with stars and stripes evoking the US flag.

There was no indication as to what caused the crash, which happened in fine, calm weather.

The worst hot-air balloon accident on record happened in Egypt in 2013, when a balloon burst into flames during a sunrise flight near the ancient city of Luxor. It crashed and killed 19 tourists.

Until that event, the deadliest hot-air balloon accident in history was an Australian catastrophe in 1989, when two hot-air balloons collided near Alice Springs, causing one balloon to crash, killing 13 people.

In New Zealand in 2012, 11 people died when a hot-air balloon hit a power line and caught fire near Carterton, north of Wellington.